Device for cutting sheets of tough or hard material



Dec. 6, 1932. p, p|KER|NG 1,890,234

DEVICE FOR CUTTING SHEETS OF TOUGH OR HARD MATERIAL Filed Feb. '7. 1930 Even/67":

PERC Y IDICKERING.

by s Whey iso Patented Dec. 6, 1932 UNITE STATES in rnncy PICKERING, 0F ninmmenninnnennnn DEVICE FOR. CUTTING SHEETS or TQUGH on tram) MATERIAL 1 Application filed February 7, 1930, Serial No.

This invention relates to devices for cut-.

ting sheets of tough or hard material, including for example fibro cement.

The object of the invention is to provide a portable, simple, and economically constructed device adapted to be manually or mechanically operated for cutting such sheets with ease and convenience. V

For this purpose I'provide a device having a top j awand a bottom jaw united at one end by a connecting piece, with cutter reciprocatable in the top jaw, and with a recess in the bottom'j aw for entrance of the edge of the cutter, and I make the top jaw of such length that at its free end it extends substantially beyond the cut made in the sheet by the cutter, and that it consequently forms an obstruction of considerable extent preventing upward curl of the sheet when the cutter is pressed against the sheet and tends to distort the same. Preferably I also lengthen the bottom jaw, to prevent downward curling,'as this is also liable to occur at times,the stresses set up by the cutting operation varying according to the conformation of the sheet, particularly with corrugated sheeting.

A tool according to th-e'invention is shown in the accompanying drawing, in which Fig. 1 is a side elevation showing the same held upright, with the jaws in vertical position.

Fig. 2 is an elevation viewed from the right hand side of Fig. 1, and

Fig. 3 is a section on the line 3-3 of Fig. 1,

In the drawing a and I) represent the two jaws, a being the top jaw when the tool is held in the usual position for a horizontal cut. The jaws a and b are connected to each other by a flat connecting piece or plate a, which iswedge shaped, as shown in Fig. 3, for a purpose to be explained hereinafter. Fixed to the jaw a is a guide 03, having one edge parallel with an edge of the plate 0, and between these parallel edges there is guided a cutter 2 working in a slot provided therefor in the jaw a. The jaw b likewise has arecess or slot, into which the edge of the cutter can enter, the width of this slot substantially exceeding the thickness of the cutter e, as is shown in Fig. 2. The edge of the cutter is 426,646, and in Australia February 9, 1959. 5 1" aslant, relatively to the parallel edges of the I jaws, for the purpose of obtaining a shearing cut. The tool has a handlef fixed tothe jaw a, and for actuating thecutter e' thereis pivoted to'the' same, at g, a double-armed lever 71. hav ng itsishorter arm engaged, by means of a stud o, with aslot 9' in the plate 0. A rubber bufler is is attached to the front part'of the handle to serve as a resilient stop limiting the 6 downward movement of the lever.

By rocking the lever h as indicated in Fig. 1 by a double-headed arrow the cutter is re ciprocated between its guides, passing across the slot between'the jaws a, b, so that when there is asheet in this slot the sameis cut. After each cut the sheet is pushed'towards the plate 0, or the tool is pulled acros's'the sheet, so that the plate a, enters the slit made in the sheet, which is of ample width to accommodate it. plate 0 wedge shaped, tapering towards the front, is that this facilitates making a curved The reason for makingthe cut, the plate being capable of being deflected slightly while in the slit of the sheet.

For cutting sheet iron the clearance at the sides of the cutters in the slotted jaw is not desirable, as a more precise shearing action is required, but this can be obtained with the same tool by placing between the jaws a thin steel plate having a slot which is accurately centered with the slot in, the lower jaw, but is narrower, this plate then coacting with the cutter to shear the sheet. The steel plate should, of course, for convenience be clamped to the lower jaw. I i

It will, of course, be understood that the tool may be designed for actuation by mechanical power, instead of manually, in which case it will be fixed to a suitable bench. The

manually actuated tool may'alsobe fixed to a bench or support, if it is desired to feed the sheetduring the cutting operation, instead of moving the tool across the sheet, but preferably the fixing is etfected in such a way as to allow of slight lateral rocking movement of the tool, to prevent undue stress being imposed on the plate 0 in the event of the tool being operated without ,duecare.

What I claim as my invention and desire .199

to secure by Letters Patent of the United States is r A sheet cutter comprising in combination a top jaw and a bottom jaw having between them a slot to receive the sheet, a cutter reciprocatable in said top jaw, a connecting piece uniting said jaws at: one end thereof,"

close to said cutter and adapted to pass through cuts made by the cutter in the sheet,

a handle fixed to said/cop aw, and mechanism including a second handle above said top" jaw for reciprocating said cutter, said bottom jaw having a recess for entrance of the edge of said cutter of awidth leaving substantial clearance on both sides of said cutter,

and-both said jaws extending at the free ends thereofsubstantially beyond thecutter, inthe direction of the cut made in the sheet,- so that obstructions of substantial length are afforded to prevent upward and downward curl of the sheet; 7 a g p 1 PERCY PIGKERING. 

